Further investigations by the tax authorities on these Suspicious Transaction Reports (STRs) resulted in detection of unaccounted income and assets of Rs 1,408 crore, they said.

An STR involves a transaction of Rs 10 lakh and above, which gives rise to a reasonable ground of suspicion that it may involve the proceeds of crime including drug trafficking and illegal money.

As many as 32,098 STRs were sent by the FIU to CBDT, under which Income Tax department functions, between January and March this year. The tax sleuths have also seized assets worth about Rs 21 crore across the country, the sources said.

The CBDT, along with its field formation of tax officials spread across the country, is in the process of concluding the probe on some of these dubious transactions.

Sources said the CBDT is in touch with agencies concerned and state governments to finish its probe in these cases.

These STRs, sent by the FIU, were regarding banking transactions including cash deposits in bank, cheque clearances, inter and intra banking dealings between individuals.